Reviewed on 3/28/2022

What Is Procainamide and How Does It Work?

Procainamide is a prescription medication used for treating symptoms of arrhythmia.

  • Procainamide is available under the following different brand names: Pronestyl (SR)

What Are Dosages of Procainamide?

Adult and pediatric dosage

Injection solution

  • 100 mg/mL
  • 500mg/mL


Adult dosage

IM Administration

  • 0.5-1 g IM every 4-8 hours

IV Administration

  • Loading dose: 100-200 mg/dose or 15-18 mg/kg; infuse slowly over 25-30 min not to exceed 50 mg/min; may repeat every 5 mins or as needed not to exceed 1 g  
  • Maintenance: 1-4 mg/min by continuous IV infusion

Pediatric dosage

IM Administration

  • 20-30 mg/kg/day IM divided every 4-6 hours; not to exceed 4 g/day

IV Administration

  • Loading dose: 3-6 mg/kg IV over 5 minutes, not to exceed 100 mg/dose; may repeat every 5-10 mins or as needed not to exceed 15 mg/kg/dose
  • Maintenance: 0.02-0.08 mg/kg/min IV infusion; not to exceed 2 g/24 hours

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Are Side Effects Associated with Using Procainamide?

Common side effects of Procainamide include:

  • mild dizziness or tired feeling;
  • flushing (warmth, redness, or tingly feeling); or
  • mild itching or rash.

Serious side effects of Procainamide include:

  • hives,
  • difficult breathing,
  • swelling of the face, lips, tongue, or throat,
  • a new or a worsening irregular heartbeat pattern,
  • chest pain, wheezing, trouble breathing,
  • a light-headed feeling,
  • signs of infection such as fever, chills, sore throat, flu symptoms, pale skin, easy bruising or bleeding (nosebleeds, bleeding gums), loss of appetite, nausea and vomiting, sores in the mouth and throat, unusual weakness,
  • depressed mood,
  •  hallucinations, 
  • severe dizziness,
  • upper stomach pain, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
  • joint pain or swelling with fever, swollen glands, muscle pain or weakness, unusual thoughts or behavior, patchy skin color, red spots

Rare side effects of Procainamide include:

  • none 
This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.


In the U.S., 1 in every 4 deaths is caused by heart disease. See Answer

What Other Drugs Interact with Procainamide?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • Procainamide has severe interactions with at least 51 other drugs.
  • Procainamide has serious interactions with at least 79 other drugs.
  • Procainamide has moderate interactions with at least 67 other drugs.
  • Procainamide has minor interactions with at least 15 other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns.

What Are Warnings and Precautions for Procainamide?


  • Hypersensitivity to procainamide or other ingredients
  • Complete heart block, 2°/3° AV block, SLE, torsade de pointes

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Procainamide?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Procainamide?”


  • May produce life-threatening hematologic disorders (leukopenia, agranulocytosis)
  • Consider toxicity if serum level is above 12 mg/L [51 umol/L]
  • May exacerbate arrhythmias or produce paradoxical ventricular tachycardia in AFib/AFlutter patients
  • Exercise caution in arrhythmias associated with digitalis intoxication; the drug can suppress digitalis-induced arrhythmias; however, concomitant marked disturbance of atrioventricular conduction may result in additional depression of conduction and ventricular asystole or fibrillation; consider use only if discontinuation of digitalis and therapy with potassium, lidocaine, or phenytoin are ineffective
  • Exercise caution if patient exhibits or develops first-degree heart block while receiving therapy; reduce dose if it occurs; if block persists despite dose reduction, evaluate whether to continue therapy by weighing benefit versus risk of increased heart block
  • Before therapy, cardiovert or digitalize patients with atrial flutter or fibrillation to avoid enhancement of A-V conduction which may result in ventricular rate acceleration beyond tolerable limits; adequate digitalization reduces but does not eliminate the possibility of a sudden increase in ventricular rate as the atrial rate is slowed by the drug in these arrhythmias
  • Use caution in patients with congestive heart failure, and those with acute ischemic heart disease or cardiomyopathy, when administering therapy; even slight depression of myocardial contractility may further reduce the cardiac output of the damaged heart
  • May produce enhanced prolongation of conduction or depression of contractility and hypotension when used concurrently with other Group 1A antiarrhythmic agents such as quinidine or disopyramide, especially in patients with cardiac decompensation; reserve such use for patients with serious arrhythmias unresponsive to single drug and administer only if the close observation is possible
  • Renal insufficiency may lead to the accumulation of high plasma levels from conventional doses of the drug, with effects similar to those of overdosage, unless the dosage is adjusted for the individual patient
  • Worsening of symptoms of myasthenia gravis may occur from therapy due to its procaine-like effect on diminishing acetylcholine release at skeletal muscle motor nerve endings; administration of therapy may be hazardous without optimal adjustment of anticholinesterase medications and other precautions
  • The injection contains sodium metabisulfite, a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people; overall prevalence of sulfite sensitivity in the general population is unknown and probably low; sulfite sensitivity is seen more frequently in asthmatic than in nonasthmatic people
  • Closely observe patients for possible hypersensitivity reactions Immediately after initiation of therapy
  • Bear in mind that the conversion of atrial fibrillation to normal sinus rhythm by any means may cause dislodgement of mural thrombi, which may lead to embolization
  • QRS monitoring
    • Continued frequent periodic monitoring of vital signs and electrocardiograms advised after achieving and maintaining therapeutic plasma concentrations and satisfactory electrocardiographic and clinical responses
    • If evidence of QRS widening of more than 25 percent or marked prolongation of Q-T interval occurs, overdosage should be considered, and interruption of the infusion is advisable if a 50 percent increase occurs
    • Elevated serum creatinine or urea nitrogen, reduced creatinine clearance or history of renal insufficiency, as well as use in older patients (over age 50), provide grounds to anticipate that less than the usual dosage or infusion rate may suffice, since the urinary elimination of PA and NAPA may be reduced, leading to gradual accumulation beyond normally-predicted amounts
    • If facilities are available for measurement of plasma procainamide and NAPA, or acetylation capability, individual dose adjustment for optimal therapeutic levels may be easier, but close observation of clinical effectiveness is the most important criterion
  • Blood pressure and ECG monitoring
    • Monitor blood pressure with patient supine during parenteral, especially intravenous, administration of the drug
    • There is a possibility that relatively high although transient plasma levels of the drug may be attained and cause hypotension before the drug can be distributed from plasma volume to its full apparent volume of distribution which is approximately 50 times greater
    • Caution should be exercised to avoid overly rapid administration of drug If blood pressure falls 15 mm Hg or more; temporarily discontinue therapy if it occurs; electrocardiographic (ECG) monitoring is advisable as well, both for observation of the progress and response of the arrhythmia under treatment, and for early detection of any tendency to excessive widening of the QRS complex, prolongation of the P-R interval, or signs of heart block
    • Parenteral therapy should be limited to use in hospitals in which monitoring and intensive supportive care are available, or to emergencies in which equivalent observation and treatment can be provided

Pregnancy and Lactation

  • Use with caution if benefits outweigh risks during pregnancy
  • Lactation
    • Crosses into breast milk, discontinue the drug, or do not nurse


See Images
Medscape. Procainamide.

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